This invention relates generally to a rotary welding apparatus for joining two metallic workpieces together by forming a circular or semi-circular weld at a semi-circular interface formed at mating surfaces of the workpieces.
Welding machines that join metallic workpieces together by forming circular or semi-circular welds at circular or semi-circular interfaces formed at mating surfaces of the workpieces are known in the art. Some of these machines are known to rotate workpieces on a common central axis while directing a laser beam at a circular or semi-circular interface between respective mating surfaces of the workpieces. The laser beam melts the first and second workpieces along the respective mating surfaces and welds the first and second workpieces together forming a circular or semi-circular weld along the circular or semi-circular interface.
It is also known for a rotary welder to include a turntable supported for rotation about a turntable axis and rotatably driven by a turntable drive. A lower tool is supported on the turntable and supports workpieces for coaxial rotation about a workpiece axis that extends through both workpieces. The turntable and lower tool support the workpieces for indexed movement along a circular workpiece path around the turntable axis between a load station and a weld station. A workpiece rotary drive connects to the lower tool when the lower tool is disposed at the weld station and rotates the lower tool about the workpiece axis. A laser emitter is supported adjacent the weld station and directs a laser beam from a laser generator toward a circular or semi-circular interface between respective mating surfaces of the workpieces as the workpiece rotary drive rotates the lower tool about the workpiece axis. The laser emitter is suspended over the turntable on an arm of a laser emitter mount. The laser emitter mount has a single support point displaced laterally from the laser emitter and outside the turntable. This laser emitter mounting arrangement allows a small but significant amount of movement between the laser emitter and the target workpieces during welding which can reduce the precision of the welding operation.
In addition, it is known to include a rotary drive that, in addition to engaging and rotating a lower tool, raises the tool to a welding position within a stationary shroud before lasing. Such shrouds are designed to protect the eyes of operators and bystanders by blocking laser energy reflected from the workpieces during welding. The rotary drive includes a vertically reciprocating pedestal that engages whichever of the tools is located at the weld station and lifts that tool and its supported workpieces into a shroud supported above the weld station. The pedestal rotates the tool and workpieces within the shroud. A laser emitter supported adjacent the weld station directs a laser beam from a laser generator toward a circular or semi-circular interface between respective mating surfaces of the workpieces, welding the workpieces together within the shroud.
According to the invention, a rotary welding apparatus is provided for joining two metallic workpieces together by forming a circular or semi-circular weld at a semi-circular interface formed at mating surfaces of the workpieces. A lower tool is configured to support first and second workpieces for coaxial rotation about a workpiece axis extending through the workpieces. The apparatus also includes a workpiece rotary drive operatively connectable to the lower tool and configured to rotate the lower tool about the workpiece axis. A laser emitter is supported adjacent the workpiece axis and is configured to direct a laser beam at a circular or semi-circular interface between respective mating surfaces of the first and second workpieces such that the laser beam melts the first and second workpieces along the respective mating surfaces and welds the first and second workpieces together. This forms a circular or semi-circular weld along the circular or semi-circular interface as the workpiece rotary drive rotates the lower tool about the workpiece axis. The resulting weld is coaxially disposed around the workpiece axis. A laser emitter mount is disposed adjacent the workpiece axis and includes a first support point displaced laterally from the laser emitter.
The laser emitter mount of the rotary welding apparatus also includes a second support point spaced radially from the first support point relative to the laser emitter to improve weld accuracy by positively locating the laser emitter relative to the workpieces.
Objects, features and advantages of this invention include rotatably supporting an upper tool on the head in a position to sandwich the workpieces between the upper tool and the lower tool before welding; including a gage block that advances radially inward to engage and hold a workpiece disposed on the lower tool during welding; and incorporating support shafts, guide rods and guide pins that maintain lateral positioning of the head and other components during axial movement. Other objects, features and advantages include simplifying construction and operation by supporting the upper tool and a shroud on a head member that is, in turn, supported on a stationary bridge mount for reciprocal axial motion relative to the bridge; mounting a portion of a shroud for axial movement on the head; converting axial head motion into lateral gage block motion using a gage block drive; supporting the gage blocks and gage block drives on a common platform; supporting the lower tool on a movable platform for indexed movement along a workpiece path between a load station and a weld station to facilitate rapid loading and unloading of workpieces; supporting the lower tool on a bearing ring the movable platform rather than on bearings disposed below the platform to minimize runout by reducing the vertical distance between the bearing and the interface to be welded; providing the bearing ring with a radius greater than that of the weld interface to further reduce runout by providing a broader, and therefore more stable rotating platform.